Anesthesia and analgesia
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Anesthesia and analgesia · Oct 1998
Randomized Controlled Trial Clinical TrialDexamethasone decreases the incidence of shivering after cardiac surgery: a randomized, double-blind, placebo-controlled study.
Shivering after cardiac surgery is common, and may be a result of intraoperative hypothermia. Another possible etiology is fever and chills secondary to activation of the inflammatory response and release of cytokines by cardiopulmonary bypass. Dexamethasone decreases the gradient between core and skin temperature and modifies the inflammatory response. The goal of this study was to determine whether dexamethasone can reduce the incidence of shivering. Two hundred thirty-six patients scheduled for elective coronary and/or valvular surgery were randomly assigned to receive either dexamethasone 0.6 mg/kg or placebo after the induction of anesthesia. All patients received standard monitoring and anesthetic management. After arrival in the intensive care unit (ICU), nurses unaware of the treatment groups recorded visible shivering, as well as skin and pulmonary artery temperatures. Analysis of shivering rates was performed by using chi2 tests and logistic regression analysis. Compared with placebo, dexamethasone decreased the incidence of shivering (33.0% vs 13.1%; P = 0.001). It was an independent predictor of reduced incidence of shivering and was also associated with a higher skin temperature on ICU admission and a lower central temperature in the early postoperative period. ⋯ Dexamethasone is effective in decreasing the incidence of shivering. The effectiveness of dexamethasone is independent of temperature and duration of cardiopulmonary bypass. Shivering after cardiac surgery may be part of the febrile response that occurs after release of cytokines during cardiopulmonary bypass.
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Anesthesia and analgesia · Oct 1998
The analgesic potency of dexmedetomidine is enhanced after nerve injury: a possible role for peripheral alpha2-adrenoceptors.
This study investigated the analgesic potency and site of action of systemic dexmedetomidine, a selective alpha2-adrenoceptor (alpha2AR) agonist, in normal and neuropathic rats. Ligation of the L5-6 spinal nerves produced a chronic mechanical and thermal neuropathic hyperalgesia in rats. von Frey fibers and a thermoelectric Peltier device were used to measure mechanical and heat withdrawal thresholds over the hindpaw. Systemic dexmedetomidine dose-dependently increased the mechanical and thermal thresholds in the control animals (50% effective dose [ED50] 144 and 180 microg/kg intraperitoneally [i.p.], respectively). Neuropathic animals responded to much smaller doses of dexmedetomidine with mechanical and thermal ED50 values of 52 and 29 microg/kg i.p., respectively. There was no difference between the control and neuropathic animals with respect to dexmedetomidine-evoked sedation, as determined by decreased grid crossings in an open-field activity chamber (ED50 12 and 9 microg/kg i.p., respectively). Atipamezole, a selective alpha2AR antagonist, blocked the analgesic and sedative actions of dexmedetomidine inboth the neuropathic and control animals. However, L-659,066, a peripherally restricted alpha2AR antagonist, could only block the analgesic actions of dexmedetomidine in the neuropathic rats, with no effect in control animals. In conclusion, nerve injury enhanced the analgesic but not the sedative potency of systemic dexmedetomidine and may have shifted the site of alpha2 analgesic action to outside the blood-brain barrier. ⋯ We tested the analgesic efficacy of the alpha2 agonist dexmedetomidine in normal and nerve-injured rats. The analgesic potency of dexmedetomidine was enhanced after nerve injury with a site of action outside the central nervous system. Peripherally restricted alpha2 agonists may be useful in the management of neuropathic pain.
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Anesthesia and analgesia · Oct 1998
Randomized Controlled Trial Comparative Study Clinical TrialComparison of patient-controlled epidural analgesia with and without background infusion after gastrectomy.
To assess the analgesic efficacy and side effects of concurrent infusion in patient-controlled epidural analgesia (PCEA) after upper abdominal surgery, 40 patients undergoing elective gastrectomy under general anesthesia were allocated to two groups in this randomized, double-blind study: one received a 2.5-mL incremental bolus in a solution of 0.2% bupivacaine and 10 microg/mL fentanyl, and the other received the same bolus dose plus a 2.5-mL/h infusion of the same solution. The number of demands was smaller (P < 0.001) in the PCEA plus infusion group than in the PCEA alone group during the 48-h postoperative period. The average hourly fentanyl and bupivacaine doses were larger (P < 0.0001) in the PCEA plus infusion group than in the PCEA alone group. Visual analog scale pain scores on coughing in the PCEA plus infusion group were lower than in the PCEA alone group (P < 0.05). There was a greater incidence of pruritus in the PCEA plus infusion group (P < 0.05), but no serious side effects were observed in either group. In conclusion, a background infusion in PCEA with a mixture of fentanyl and bupivacaine decreases the incidence of postoperative pain and reduces the degree of pain associated with coughing without serious side effects after gastrectomy. ⋯ A background infusion in patient-controlled epidural analgesia with a mixture of fentanyl and bupivacaine decreased the incidence of postoperative pain and reduced the degree of the pain associated with coughing without serious side effects in this randomized, double-blind study after gastrectomy.
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Discharge time (total recovery time) is one determinant of the overall cost of outpatient surgery. We performed this study to determine what factors affect discharge time. Details regarding patients, anesthesia, surgery, and recovery were recorded prospectively for 1088 adult patients undergoing ambulatory surgery over an 8-mo period. The contribution of factors to variability in the discharge time was assessed by using multivariate linear regression analysis. In the last 4 mo of the study, nurses indicated the causes of discharge delays > or =50 min in Phase 1 or > or =70 min in Phase 2 recovery. When all anesthetic techniques were included, anesthetic technique was the most important determinant of discharge time (R2 = 0.10-0.15; P = 0.001), followed by the Phase 2 nurse. After general anesthesia, the Phase 2 nurse was the most important factor (R2 = 0.13; P = 0.01-0.001). In women, the choice of general anesthetic drugs was significant (R2 = 0.04; P = 0.002). The three most common medical causes of delay were pain, drowsiness, and nausea/vomiting. System factors were the foremost cause of Phase 2 delays (41%), with lack of immediate availability of an escort accounting for 53% of system-related delays. We conclude that efforts to shorten discharge time would best be directed at improving nursing efficiency; ensuring availability of an escort for the patient; and preventing postoperative pain, drowsiness, and emetic symptoms. The selection of anesthetic technique and anesthetic drug seems to be of selective importance in determining discharge time depending on patient gender and type of surgery. ⋯ The relative importance of anesthetic and nonanesthetic factors were evaluated as determinants of discharge time after ambulatory surgery. Postoperative nursing care was the single most important factor after general anesthesia; anesthetic drugs, anesthetic technique, and prevention of pain and emetic symptoms were of selective importance depending on patient gender and type of surgery.
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Anesthesia and analgesia · Oct 1998
Infraclavicular brachial plexus block: parasagittal anatomy important to the coracoid technique.
Infraclavicular brachial plexus block is a technique well suited to prolonged continuous catheter use. We used a coracoid approach to this block to create an easily understood technique. We reviewed the magnetic resonance images of the brachial plexus from 20 male and 20 female patients. Using scout films, the parasagittal section 2 cm medial to the coracoid process was identified. Along this oblique section, we located a point approximately 2 cm caudad to the coracoid process on the skin of the anterior chest wall. From this point, we determined simulated needle direction to contact the neurovascular bundle and measured depth. At the skin entry site, the direct posterior insertion of a needle will make contact with the cords of the brachial plexus where they surround the second part of the axillary artery in all images. The mean (range) distance (depth along the needle shaft) from the skin to the anterior wall of the axillary artery was 4.24 +/- 1.49 cm (2.25-7.75 cm) in men and 4.01 +/- 1.29 cm (2.25-6.5 cm) in women. Hopefully, this study will facilitate the use of this block. ⋯ We sought a consistent, palpable landmark for facilitation of the infraclavicular brachial plexus block. We used magnetic resonance images of the brachial plexus to determine the depth and needle orientation needed to contact the brachial plexus. Hopefully, this study will facilitate the use of this block.